scholarly journals Selective phosphorylation of the IP3R-I in vivo by cGMP-dependent protein kinase in smooth muscle

2003 ◽  
Vol 284 (2) ◽  
pp. G221-G230 ◽  
Author(s):  
Karnam S. Murthy ◽  
Huiping Zhou

This study examined the expression of inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) types and PKG isoforms in isolated gastric smooth muscle cells and determined the ability of PKG and PKA to phosphorylate IP3Rs and inhibit IP3-dependent Ca2+ release, which mediates the initial phase of agonist-induced contraction. PKG-Iα and PKG-Iβ were expressed in gastric smooth muscle cells, together with IP3-R-associated cG-kinase substrate, a protein that couples PKG-Iβ to IP3R-I. IP3R-I and IP3R-III were also expressed, but only IP3R-I was phosphorylated by PKA and PKG in vitro and exclusively by PKG in vivo. Sequential phosphorylation by PKA and by PKG-Iα in vitro showed that PKA phosphorylated the same site as PKG (presumably S1755) and an additional PKA-specific site (S1589). In intact muscle cells, agents that activated PKG or both PKG and PKA induced IP3R-I phosphorylation that was reversed by the PKG inhibitor (8R,9S,11s)-(−)-9-methoxy-carbamyl-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy-1H,8H,1H,-2,7b,11a-trizadizo-benzo9(a,g)cycloocta(c,d,e)-trinden-1-one. Agents that activated PKA induced IP3R-I phosphorylation in permeabilized but not intact muscle cells, implying that PKA does not gain access to IP3R-I in intact muscle cells. The pattern of IP3R-I phosphorylation in vivo and in vitro was more consistent with phosphorylation by PKG-Iα. Phosphorylation of IP3R-I in microsomes by PKG, PKA, or a combination of PKG and PKA inhibited IP3-induced Ca2+ release to the same extent, implying that inhibition was mediated by phosphorylation of the PKG-specific site. We conclude that IP3R-I is selectively phosphorylated by PKG-I in intact smooth muscle resulting in inhibition of IP3-dependent Ca2+ release.

1994 ◽  
Vol 269 (11) ◽  
pp. 8504-8509
Author(s):  
K.A. Pritchard ◽  
M.K. O'Banion ◽  
J.M. Miano ◽  
N. Vlasic ◽  
U.G. Bhatia ◽  
...  

2005 ◽  
Vol 108 (6) ◽  
pp. 523-530 ◽  
Author(s):  
Giovanna CASTOLDI ◽  
Serena REDAELLI ◽  
Willy M. M. van de GREEF ◽  
Cira R. T. di GIOIA ◽  
Giuseppe BUSCA ◽  
...  

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.


2015 ◽  
Vol 37 (5) ◽  
pp. 1817-1829 ◽  
Author(s):  
Kai Huang ◽  
Zhi-Qiang Yan ◽  
Dan Zhao ◽  
Si-Guo Chen ◽  
Li-Zhi Gao ◽  
...  

Background/Aims: Physiological mechanical stretch in vivo helps to maintain the quiescent contractile differentiation of vascular smooth muscle cells (VSMCs), but the underlying mechanisms are still unclear. Here, we investigated the effects of SIRT1 in VSMC differentiation in response to mechanical cyclic stretch. Methods and Results: Rat VSMCs were subjected to 10%-1.25Hz-cyclic stretch in vitro using a FX-4000T system. The data indicated that the expression of contractile markers, including α-actin, calponin and SM22α, was significantly enhanced in VSMCs that were subjected to cyclic stretch compared to the static controls. The expression of SIRT1 and FOXO3a was increased by the stretch, but the expression of FOXO4 was decreased. Decreasing SIRT1 by siRNA transfection attenuated the stretch-induced expression of contractile VSMC markers and FOXO3a. Furthermore, increasing SIRT1 by either treatment with activator resveratrol or transfection with a plasmid to induce overexpression increased the expression of FOXO3a and contractile markers, and decreased the expression of FOXO4 in VSMCs. Similar trends were observed in VSMCs of SIRT1 (+/-) knockout mice. The overexpression of FOXO3a promoted the expression of contractile markers in VSMCs, while the overexpression of FOXO4 demonstrated the opposite effect. Conclusion: Our results indicated that physiological cyclic stretch promotes the contractile differentiation of VSMCs via the SIRT1/FOXO pathways and thus contributes to maintaining vascular homeostasis.


2007 ◽  
Vol 22 (2) ◽  
pp. 579-589 ◽  
Author(s):  
Daniel G. Sedding ◽  
Matthias Homann ◽  
Ulrike Seay ◽  
Harald Tillmanns ◽  
Klaus T. Preissner ◽  
...  

2020 ◽  
Vol 224 ◽  
pp. 40-54 ◽  
Author(s):  
Joaquim Bobi ◽  
Manel Garabito ◽  
NÚria Solanes ◽  
Pilar Cidad ◽  
Víctor Ramos-Pérez ◽  
...  

2019 ◽  
Vol 68 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Annele Sainio ◽  
Piia Takabe ◽  
Sanna Oikari ◽  
Henriikka Salomäki-Myftari ◽  
Markku Koulu ◽  
...  

Metformin is the first-line drug in the treatment of type 2 diabetes worldwide based on its effectiveness and cardiovascular safety. Currently metformin is increasingly used during pregnancy in women with gestational diabetes mellitus, even if the long-term effects of metformin on offspring are not exactly known. We have previously shown that high glucose concentration increases hyaluronan (HA) production of cultured human vascular smooth muscle cells (VSMC) via stimulating the expression of hyaluronan synthase 2 (HAS2). This offers a potential mechanism whereby hyperglycemia leads to vascular macroangiopathy. In this study, we examined whether gestational metformin use affects HA content in the aortic wall of mouse offspring in vivo. We also examined the effect of metformin on HA synthesis by cultured human VSMCs in vitro. We found that gestational metformin use significantly decreased HA content in the intima-media of mouse offspring aortas. In accordance with this, the synthesis of HA by VSMCs was also significantly decreased in response to treatment with metformin. This decrease in HA synthesis was shown to be due to the reduction of both the expression of HAS2 and the amount of HAS substrates, particularly UDP-N-acetylglucosamine. As shown here, gestational metformin use is capable to program reduced HA content in the vascular wall of the offspring strongly supporting the idea, that metformin possesses long-term vasculoprotective effects.


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